for the Thyroid Studies Collaboration C ONTROVERSY PERSISTS ON THEindications for screening and threshold levels of thyroidstimulating hormone (TSH) for treatment of subclinical hypothyroidism, 1-3 defined as elevated serum TSH levels with normal thyroxine (T 4 ) concentrations. Because subclinical hypothyroidism has been associated with hypercholesterolemia 4 and atherosclerosis, 5 screening and treatment have been advocated to prevent cardiovascular disease. 3 However, data on the associations with coronary heart disease (CHD) events and mortality are conflicting among several large prospective cohorts. [6][7][8][9] Three recent study-level metaanalyses 10-12 found modestly increased risks for CHD and mortality, but with heterogeneity among individual studies that used different TSH cutoffs, dif-See also Patient Page. CME available online at www.jamaarchivescme.com and questions on p 1392.
We investigated possible associations between subclinical hypothyroidism and atherosclerotic diseases (ischemic heart disease and cerebrovascular disease) and mortality. Of 2856 participants (mean age 58.5 yr) in a thyroid disease screening between 1984 and 1987, 257 subjects with subclinical hypothyroidism (TSH > 5.0 mU/liter) and 2293 control subjects (TSH range 0.6-5.0 mU/liter) were analyzed. In the baseline cross-sectional analysis, subclinical hypothyroidism was associated with ischemic heart disease independent of age, systolic blood pressure, body mass index, cholesterol, smoking, erythrocyte sedimentation rate, or presence of diabetes mellitus [odds ratio (OR), 2.5; 95% confidence interval (95% CI), 1.1-5.4 in total subjects and OR, 4.0; 95% CI, 1.4-11.5 in men] but not in women. However, there was no association with cerebrovascular disease (OR, 0.9; 95% CI, 0.4-2.4). We were unable to detect an influence of thyroid antibody presence on the association between subclinical hypothyroidism and ischemic heart disease. In a 10-yr follow-up study until 1998, increased mortalities from all causes in yr 3-6 after baseline measurement were apparent in men with subclinical hypothyroidism (hazard ratio, 1.9-2.1) but not in women, although specific causes of death were not determined. Our results indicate that subclinical hypothyroidism is associated with ischemic heart disease and might affect all-cause mortality in men.
IMPORTANCE-Associations between subclinical thyroid dysfunction and fractures are unclear and clinical trials are lacking. OBJECTIVE-To assess the association of subclinical thyroid dysfunction with hip, nonspine, spine, or any fractures. DATA SOURCES AND STUDY SELECTION-The databases of MEDLINE and EMBASE (inception to March 26, 2015) were searched without language restrictions for prospective cohort studies with thyroid function data and subsequent fractures. DATA EXTRACTION-Individual participant data were obtained from 13 prospective cohorts in the United States, Europe, Australia, and Japan. Levels of thyroid function were defined as euthyroidism (thyroid-stimulating hormone [TSH], 0.45-4.49 mIU/L), subclinical hyperthyroidism (TSH <0.45 mIU/L), and subclinical hypothyroidism (TSH ≥4.50-19.99 mIU/L) with normal thyroxine concentrations. MAIN OUTCOME AND MEASURES-The primary outcome was hip fracture. Any fractures, nonspine fractures, and clinical spine fractures were secondary outcomes.RESULTS-Among 70 298 participants, 4092 (5.8%) had subclinical hypothyroidism and 2219 (3.2%) had subclinical hyperthyroidism. During 762 401 person-years of follow-up, hip fracture occurred in 2975 participants (4.6%; 12 studies), any fracture in 2528 participants (9.0%; 8 studies), nonspine fracture in 2018 participants (8.4%; 8 studies), and spine fracture in 296 participants (1.3%; 6 studies). In age-and sex-adjusted analyses, the hazard ratio (HR) for subclinical hyperthyroidism vs euthyroidism was 1.36 for hip fracture (95% CI, 1.13-1.64; 146 events in 2082 participants vs 2534 in 56 471); for any fracture, HR was 1.28 (95% CI, 1.06-1.53; 121 events in 888 participants vs 2203 in 25 901); for nonspine fracture, HR was 1.16 (95% CI, 0.95-1.41; 107 events in 946 participants vs 1745 in 21 722); and for spine fracture, HR was 1.51 (95% CI, 0.93-2.45; 17 events in 732 participants vs 255 in 20 328). Lower TSH was associated with higher fracture rates: for TSH of less than 0.10 mIU/L, HR was 1.61 for hip fracture (95% CI, 1.21-2.15; 47 events in 510 participants); for any fracture, HR was 1.98 (95% CI, 1.41-2.78; 44 events in 212 participants); for nonspine fracture, HR was 1.61 (95% CI, 0.96-2.71; 32 events in 185 participants); and for spine fracture, HR was 3.57 (95% CI, 1.88-6.78; 8 events in 162 participants). Risks were similar after adjustment for other fracture risk factors. Endogenous subclinical hyperthyroidism (excluding thyroid medication users) was associated with HRs of 1.52 Blum et al.
Background-Early repolarization pattern is a common ECG finding characterized by J-point elevation and QRS notching or slurring in the inferior and/or lateral leads, yet little is known about its incidence and long-term prognosis in Asian populations. Methods and Results-We reviewed all the ECG records of the 5976 atomic-bomb survivors who were examined at least once during our biennial health examination in Nagasaki, Japan, between
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.